Information on Hansen's Disease

Top What is Hansen's Disease? Information on Hansen's Disease

Information on Hansen's Disease

Hansen's disease

Hansen's disease (leprosy) is a type of infectious disease caused by a bacterium called "Mycobacterium leprae." The disease used to be called "Rai" in Japanese, but because of its discriminatory image, it is now called "Hansen's disease," after Armauer Hansen, who discovered leprosy.

Cause of onset

Bacteria that cause leprosy are not strong enough to cause the disease and will not cause the disease in most cases, even if the bacteria enter the body due to the immune system. However, the disease may develop in people who came in repeated contact with untreated leprosy patients during infancy due to the weakened immune system. The risk of developing the disease with poor nutrition and hygiene increases as the immune function is lowered.

Symptoms of Hansen's disease

Hansen's disease affects the skin and peripheral nerves. The disease is a chronic infection that progresses slowly after the onset. The initial symptoms are skin lesions called rashes and sensory paralysis that causes the loss of sensation of pain and heat. If the disease progresses without treatment, it leads to movement disorders and deformities in the limbs and face. Limb deformities interfere with daily activities such as picking up objects and walking.


Early symptom of rash

Treatment of Hansen's disease

Hansen's disease is cured by spontaneous recovery in some cases, but in the days when there was no cure, the disease could not be treated medically. In 1941, a drug called Promin effective for Mycobacterium leprae was introduced in the U.S., and Hansen's disease became a disease that could be cured. Since then, there has been progress in improving the drugs, and multidrug therapy has been established in which two to three different medications are taken for one to two years. Medications are distributed free of charge by WHO. Once the patient starts the multidrug therapy, Mycobacterium leprae loses its infectivity within a few days.
In this way, Hansen's disease can be cured by treatment with only medicines. Hansen's disease is a common disease that does not require hospitalization and can be treated while the afflicted person continues going to work or school.


WHO distribution remedy


Although Hansen's disease is cured without leaving any disability if treatment is started early, sequelae are observed in people in whom the disease had progressed when there was no cure or those for whom the treatment has been delayed. In addition to disorders caused by Hansen's disease, such as sensory paralysis and movement disorders, there are cases of amputation of limbs and fingers. This is because people with paralysis do not feel pain when injured, so they do not take care of the injury or are unaware of the injury. As a result, the injury may worsen and may require amputation. However, a person cured of the disease will not be the source of infection, even in sequelae.

Incidence of leprosy in Japan

Only a few new cases are reported every year in Japan, with foreigners living in Japan accounting for most of the cases. It is considered that the patients in such cases were already infected before coming to Japan and developed the disease due to lowered immune function caused by working hard and leading a harsh life in Japan. At present, there are very few cases of people born and raised in Japan who develop Hansen's disease. In addition to the good nutrition and hygiene conditions in Japan today, this can be attributed to the fact that there are no patients who can be infectious. Japanese people rarely develop leprosy; however, there are cases where people who have been infected but are free of symptoms develop the disease due to a decline in immune function associated with aging, or cases where people who have been cured of the disease once have recurrence due to a decline in immune function for some reason. However, if we look overseas, there are more than 200,000 new cases annually, mainly in developing countries where nutrition and hygiene conditions are not good.